Buttonhole cutting and stitching machine



E. B. ALLER. BUTTONHOLE CUTTING AND STITCHING MACHINE.

APPL ICAT'IOH FILED MAR. 20; i920. 1,380,339, Patented'June W2 4 SHEETS-8;? v5;"? 1.

ATTORNEY INVENTOR 6W AZ W E. B. ALLEN.

TITCHING MACHINE IAPPLICATIONIILED MAR. 20, 1920.

BUTTONHOLE CUTTiNG AND S Patented June 7, 1921.

ATTORNEY 4 SHEETS-SHEET 2.

WITNESSES:

E. B. ALLEN. I BUTTO NH O'I.E CUTTING AND STITCHING MACHINE.

APPLICATION FILED MAR. 20, 1920.

EEFI

Patented June 7, 1921.

4 SHEETS-SHEET 3.

. INVENTOR 20334 an;

' WITIINESYSEIS: I 3% ATTORNEY E. B. ALLEN.

BUTTONHOLE CUT-TING ANDv STITCHING MACHINE.

APPLICATION FILED MAR. 20. I920.'

L 94 9F. m. au S MT .E M 8 m. n .w a P ATTORNEY INVENTOR WITNESSES; mn/fiewa UNITED, STATES PATENT OFFICE.

EDWARD B. ALLEN, OF NEWTOWN, CONNECTICUT, ASSIGNOR TO THE SINGER MANU- FACTURING COMPANY, OLE ELIZABETH, NEW' JERSEY, A CORPORATION NEW JERSEY.

IBU'TTONHCLE CUTTING AND STITCHING MACHINE.

Patented-June 7, 1921.

Application filed March 20, 1920. Serial No. 367,297;

To ail ID/107R may concern:

Be it known that I, EDWARD B. ALLEN, a citizen of the United States, residing at Newtown, in the county of Fairfiold and State of Connecticut, have invented certa1n new and useful Improvements in Buttonhole Cutting and Stitching Mach nes, of which the following is a specificat1on,reforence being had therein to the accompanying drawings.

In gap or eyelet=end buttonhole sew ng machines employing buttonhole ,cuttmg mechanism oi the type comprising a sharpened knife which operates to cut the buttonhole upon a flat anvil or brass, dl'liiculty has always been experienced in pre-' venting the cuttings from dropping out of the eye or aperture in the cutter. I'h'ese cuttings often fall upon the work within the range or action of the stitching instrumentalities, and are sewed in, or covered by the ovcrseam, thus marring the appearance of the work. Further, with the knife-andbrass type or" cutter, no material is removed from the buttonhole slit, excluding the eye, 211M it is necessary to provide means :lor spreading the work laterally of the buttonhole slit to separate the cut edges suiliciently to admit the lower curved needle, This spreading action, in a machine having a knii'c andbrass buttonhole cutter must be of relatively considerable magnitude. If the work is of uneven thickness or texture it is apt to be stretched more at one thanat the other side of the buttonhole slit, whereby the slit is in eilcct pulled to one sideoi the central position and out of register with the sewing instrumentalities. The result isan imperfect buttonhole. Attempts have been made to overcome these and other disadvantagcs incident to the use of the knife-andan viltype of cutter by using a cutter of the puiu-h-and-die type, wherein a narrow strip of material is removed to form the buttonhole slit and is forced into a die at the under Hide of the material. In the machine disclosed in my Patent No. 864,144, dated August 27, 190?, a punch-and -die cutter is used, but in this machine the buttonhole is cut in sewing position and it has been found impractical to provide the necessary clearance between the die and the stitch-forming instrumentalities while maintaining asturdy and durable construction, particularly of the die member. Further, in themachine of my said patent the stitch-forming mechanism is of the so-called I. B. H. type embodying an upper reciprocatory and laterally vibrating needle which forms slit anrwdepth stitches alternately in conjunction with lower thread-handling devices 'or' loopers operating wholly beneath the plane ner of the buttonhole slit. This sawing action causes the thread tocut into or embed itselt' in the sharp corner of the work thereby permitting said corner to protrude or show through the overedge stitches. Inasmuch as the needle-thread cuts into the sharp corner of the work at the points of initial contact therewith and inasmuch as the points of initial contact are of uncertain and more or less haphazard spacing, it results that the overedge stitches are unevenly spaced along the buttonh'ole and, being embedded, cannot slide along or dis tribute themselves evenly when being set. The present invention has for an object to provide a buttonhole sewing machine which will operate with a minimum of care and attention to produce uniformly perfect but-tonholes of superior finish and appearance under usual factory operating conditions.

A further object of the invention isto improve the machine disclosed in my copending application Serial No. 317,902, tiled Aug. 16, 1919 of which this application is a continuation in part. Heretoiore, it has been customary to provide a buttonhole cutter comprising a traveling fulcrum-block on which is pivotally mounted a pair of cutter-levers, the forwardly extending arms of which carry coacting buttonhole cutting elements and the rearward arms of, which are connected by a coil-spring and extend above and below suitable cutter-closing cams on a so-called cutter-shaft which is automatically controlled and makes a single totetion for each buttonhole producin cycle. During the action of the stitchor mechanism, the cutter levers and their 'fu crum block occupy a retracted or out of the way position so as not to interfere with the movements of the stitch-forming instrumentalities. \Vhen the buttonhole is to be cut, however, the traveling fulcrum block advanced toward the stitch-forming mechanism and carries the cutter levers to cutting position wherein they are closed upon the work by the cutter-closing cam 0 cams.

a clamping ,plates and upper pivotall mountt ed clamping feet. The clamping p ates and feet are, so formed as to provide upper and Iowerregistering apertures exposing the material-to the action of the bnttonhode cutting and stitch-forming instrumentalities, while clam 'ing it securely on all sides of the expose portion. During-the buttonhole cutting operation the cutting elements are brought tqgether or closed through the work-exposing aperture of the work-clamp and if the cutting elements are not separated preparatory to their withdrawal to inactive position, damage to the machine will result. In prior machines with which I am familiar the coilspring which connects the rearwar pended upon to'separate the cutting elements preparatory to retraction of the latter to inactive position. If this spring should break at an inopportune time the cutters and work-clamp would be damaged.

The buttonhole cutting .elements mounted onthe forwardly extend ng arms of the buttonhole cutter-levers commonly comprise a knife elementwhich is sharpened to a knife edge and coiiperates with a fiat anvil element or brass, to cut the buttonhole. With cuttin elements of this type, no particular diflicu ty is encountered in separating said elements by means of a coil spri after the cutting stroke, In the machine disclosed in my said copending application, however, the cutting elements are of the punch-and-die type, as distinguished from the knife-andanvil type; the upper or punch member being curved concentrically with the axis of pivotal movement of its supporting lever, and the under member having the form of a die, the a erture of which receives the extremity o the punch element. With a but tonhole cutter of this latter type, it is found that thecurved .punch element is liable at times to stick in the die element; the force of the coil spring being insufficient to sepaends of the cutter levers is de-- rate said elements after the cutting stroke. To materially increase the strength of the spring would be to put a heavy load on the cutter-shaft and thereby cause considerable wear and tear on the parts.

With the above considerations in view, another object of the invention is to provide light running actuating mechanism which will close and open the coacting elements of a pivoted buttonhole cutter, with a positive action, as distinguished from the yielding and uncertain action incident to the use of a s ring.

A further t of the invention is to provide simplifie and improved means assoeiated with the buttonhole cutting mechanism for closing the work-clam common to machines of the present type. have discovered that the disadvantages of-the punchand-die type of cutter in a buttonhole sewing machine can be eliminated by combining such cutter with stitch-forming mechanismof the so-called H and H type embodying an upper straight needle and a lower curved needle such for example as dis closed in my Patent No, 1,162,207, of November 30, 1915. I have found that with stitch-forming mechanism of this type, the overedge thread carried by the curved needle can be run under a light tension and does not reeve or saw across or become embedded in the sharp up or corner of a buttonhole slit produced y a punch-and-dio cutter but, on the contrary, does distribute itself evenly and uniformly along the length of the buttonhole slit and satisfactorily covers :the sharp upper corner of the material around the slit. -As, the lower curved needle rises through the buttonhole slit and pre sents its loop to the u per or deptlnstitch needle, the lower thread 15 not taut and as the upper needle descends, the upper thread binds one limb of the lower needleloop in final position over the edge of the work. As the curved needle descends, its thread is held clear of the work by said needle until the eye of said needle descends below the work, whereupon the other limb of the lower needle loop is laid in position over the edge of the work without any reeving or sawing action over said vedge. In other words, the supply limb of the lower needle loop is held clear of the work by the curved needle until said loop is reduced to finished size which size is reached just as the eye of the lower needle is descending below the level of the work and is laying the supply limb of the curved needle loop-over the edge of the work. It has been discovered by. experiment that this action-of stitch-forming mechanism of the u per depth stitch needle and lower curve slit stitch needle type, peculiarly and unexpectedly coiiperates with the buttonhole cutting mechanism of the punch-anddie type, to produce stitched buttonholes of superior finish and remarkably uniform appearance in materials of varying qualities, thicknesses and textures.

-According to the present improvement it is preferred to cut the buttonhole out of stitching position. The punch element of the cutter is preferably mounted directly upon a pivoted carrier lever and is curved concentric with the axis of pivotal move m nt of said lever. Adjustments are pros vided for the punch-and-die elements to insure exact registry .of the buttonhole slit with the stitched pattern produced by the machine.

The usual cutter-shaft which makes a single revolution during each buttonholeproducing cycle is preferably provided, in addition to the usual cutter-advancing cam, with cutter-actuating cams of the closed type. In the embodiment of the invention illustrated, these cams serve to vibrate a pair of auxiliary cutter levers whichat their rearward ends are pivoted to the machine frame at fixed points. At their forward ends these auxiliar T levers are formed With longitudinally extending slots which are entered by lateral rolls carried at the rear ends of the respective cutter-levers; the latter being. fulcrumed on a traveling fulcrum-block and at their front ends carrying the cutting elements. The roll and slot connections between the cutter-levers and the auxiliary levers permit the cutter-levers to be shifted forwardly from retracted to cutting position while maintaining their operative connection with the auxiliary levers. Since the cutteractuating cams are of the closed type, they operate to positively close and positively separate the cutting elements, and insure against damage to the machine resulting from a failure to separate the cutting ele ments prior to their retraction.

The present organization includes a clampclosing lever which is fulcrumed at a fixed point on the frame of the machine and is 0peratively connected with the auxiliary lever which operates the lower or die element of the buttonhole cutter. It is found that if the said die element, while in retracted position, is maintained at a level somewhat above the surface of the lower work-clamping plates. that it can be established closer to buttonhole cutting position without interfering with the movements of the stitchforming instrumentalities carried by the lower rotary turret, than if said the element is maintained at alower level.

However, in order to secure the saving in time and other advantages incident to a minimum traveling movement of the buttonhole cutter, it is found necessary to give a dip to the die element during the first part of its advancin movement to carry it under the lower work-clamping plates. The movement of the respective auxiliary lever in givelevation of the same.

ing the necessary dip to the die element prior to the buttonhole cutting operation is utilized in the present instance to close the work-clamp before the latter is shifted toward cutting position.

In the accompanying drawings, Figure 1 is a side elevation, partly in section, of a buttonhole cutting and stitching machine embodying the invention. Fig. 1 is a fragmentary front elevation of the head at the free end of the bracket-arm of the machine. Fig. 2 is a plan view of the machine bed showing the bracket-arm standard in horizontal section. F ig. 2 is a detail perspective view of the latch at the free end of one of the work-clamping arms. Fig. 2 is a fragmentary plan view of the lower work-supporting plates. Fig. 3 is a side elevation of the buttonhole cutting and clamp-closing mechanism, the cutter-levers being in retracted position. Fig. 4 is a similar view showing tl1e.,movement of the clamp-closing lever as the die element of the buttonhole cutter is given a dip to carry it under the lower work-clamping plates during its advance to cutting position. Fi 5' is a View similar to Figs. 3 and 4 but showing the buttonhole cutter and work-clamp in cutting position. Fig. 6 is a side elevation on an enlarged scale of the punch and die elements of the buttonhole cutter. Fig. 7 is a front Fig. 8 is a front elevation of the upper or punch element. Fig. 9 is a plan view of the adjustable abutment block for the punch element. Fig. 10 is a plan view of the die element and Figs. 11' and 12 are. cross sectional views on the lines 1111 and 12-12. respectively, Fig. 6.

For the purposes of the present disclosure the invention is embodied in a machine constructed substantially in accordance with the disclosure of my said copending applica-.

an upper eyepointed needle 5 which is carried by the needle-bar 6 journaled in the head 4: for the usual reciprocating and axial turning movements. The reciprocating movements are derived from the usual pitman '7 and crank-pin 8 at the forward end of the 'needlebar actuating shaft 9 extending within and lengthwise of the bracket-arm 3. This shaft carries a bevel-gear 9 which meshes with a companion gearlO of twice its size fixed to the upper end of the vertical shaft 11 journaled within the standard 2 and at its lower end carrying abevel gear 12 which meshes with the driving gear 13 on the main or sewing shaft 14 journaled within and lengthwise of the hollow base 1.

The needle 5 cooperates with the usual lower stitch-forming instrumentalities including the curved needle 15 carried by the usual rotary turret 15 mounted to turn within the curb 16 about a vertical axis-coincident with the axis of the needle-bar 6. During the. sewing operation the ncedlebar and turret receive simultaneous step-bystep turning movements from the upper and lower sector-gears 17 and 18, respectively. These gears are connected in the usual mannerto a vertical shaft 19 to move in unison and are operated from the feed-wheel 20, all as more fully set forth in my said Patent No. 1,162,207, and in my Patent No. 1,346,102, granted July 13, 1920.

Supported upon the rotary turret together with the supporting post 15 for the curved needle 15 is a post 21 carrying the usual needle-throat or button 22 which is formed with the usual crescent-shaped aperture 23 through the extremities of which the upper and lower needles are adapted to pass, Unlike the construction disclosed in my said Patent No. 1,162,207, the present support for the needle-throat is not mounted for tilting movement to permit the advance of the but tonhole cutter, but is rigid with the turret at all times.

The work-holder is preferably of the usual traveling type which, however, in the embodiment of the invention chosen for the purposes of the present disclosure. receive only lateral com )onents of motion from the feed wheel 20. other words, the particular worksholder illustrated is moved CIOSswise only of the bed 1 during the sewing operation. \Vhile any suitable type of workholder may be used, I prefer to employ a work-holder which is constructed substantially in accordance with the disclosure of my .said copending application Serial No. 317,902. Such a work-holder comprises the lower work-supporting or clamping plates 24 which are mounted as usual upon a cross slide-plate 25; the latter being, in turn. carried by the longitudinal slide-frame 26.

The work-supportingplates 24 are formed in their meeting edges 27 with complemental notches afl'ording an elongated aperture 28 extending cross-wise of the bed 1 and transversely of the standard 2 and bracket-arm 3 of the machine frame. This aperture receives the needle-throat 22 during the sewing operation, as shown in Figs. 2 and 4,

and consequently embraces the paths of.

movement of the upper and lower needles which pass through the extremities of the crescent-shaped aperture 23 in the needlethroat. The aperture 28 in the lower clampplates has straight and uninterrupted front and rear sides along which the work is firmly clamped by means of the clam ing foot 29. One of the work-clamping p ates 24 is formed with an additional aperture 30 which is spaced forwardly of the aperture 28 and receives. the needle-throat when the work-holder is shifted to cutting position, as shown in Fig. 5. This latter aperture is separated from the elongated aperture 28 by a tongue 31 which assists in supporting the work against the pressure of the clamping foot 29 and enables the work to be firmly clamped along the entire front side of the buttonhole-slit.

The lower clamping plates 24 carry the brackets 32 within whieh'are fulcrumed at- 33 the rearward ends of the usual upper clamping arms 34 which, in the present instance. carry at their forward ends the previously mentioned clamping foot 29; the after being formed with an elongated aperture 35, F 1g. 2, extending crosswise of the bed 1 and adapted to register with the elongated aperture 28 in-the work-supporting plates. The under surface of the foot 29, being roughened, operates to securely clamp the work against the roughened upper surface adjacent the aperture 28.

The foot 29 is secured at one end to the forward extremity of one of the clamping arms 34 by the screw 36 and at its other end carries a screw 37 the shank of which is received within the notch 38 at the forward extremity of the other clamping arm and held therein by means of the pivoted latch 39. Upon opening the latch 39, the foot :19 may be swung about the screw 36 as a pivot to expose the needle-throat 22 and other parts stationed below said foot. It to be understood that the screws 36 and 37 do not fit theapertures in the arms 34 so tightly as to prevent the foot from tilting slightly to accommodate itself to inequalities in the work and exert an even pressure thereon at opposite sides and ends of the buttonhole-sht.

The work-clamp includes the usual alined clamp-closing rock-shaft sections 40, 40 which are connected to move in unison by means of the usual offset fork-and-pin device 41. Each of the rock-shaft sections 40 carries a cam 42 for depressing its respective arm 34 to close the clam One of the shaft sections 40 carries a nger-piece 43 and a rearwardly extending arm 44, movement of either of which serves to rock the shaft sections 40 and close the clamp which is latched in closed osition in a manner well understood and isclosed, for example, in my eopending application Serial No. 204,842, filed December 1 1917.

It is understood that the feed-wheel 20 has in its upper surface a cam-groove 45 which operates through the usual lever connection 46, such as disclosed in my Patent No. 1,039,241, of September 24, 1912 to impart ing block the necessary step-by-step feeding motion to the workholder crosswise of the machine bed 1. Step-by-step rotary motion is imparted to the feed-wheel through the usual gear connections 47 Fig. 1, with the starwheel 48 whioh'is driven by the diametrically opposed pins 49 at the lower end of the shaft i l, as morefully disclosed in my said copcndiug application Serial No. 217,483.

The present machine preferably embodies an auxiliary shaft 50 which performs a 7 toward and away from the clutch tooth 54.

The huttouhole cutter of the machine is of the punch-and-die type which removes an elongated section of the material from end to end of the buttonhole slit and may he i'ronstructed substantially in accordance with the disclosure of my said copei'iding application Serial No. 317,902. The cutter comprises the usual traveling fulcrum block 57 on which are pivoted at the upper and lower cutter levers 59 and 60, respectively.

The upper cutter-lever 59 is formed with a curved seat 59, Fig. 6, which is concentric with the fulcrum screw 58, Fig. 5, about which said lever is tilted. The upper punch element 61 is in the form of a flat blade curved flatwise concentrically with the axis of the pivot-screw 58 and is clamped against the curved seat 59 by means of the clamp- 59 and screw 59 which passes through enlarged apertures 59 and 59 in the block and punch-element. The lever supports a curved block 59 which is clamped to the seat59 by means of the screw 59 which. passes through the slot 59 in. said block, permitting adjustment of the block lengthwise of the seat 59 to bring the shoulder 59 at the front or lower edge of said block into abutting relation with the squared off rearward end of the punch element 6i.

i /hon. the punch elcment 61 is replaced after having been removed for sharpening, it may be adjustedendwise, in the path of its operative movement to enter the die 62 the correct distance, after which the abutment bl-ick 59 is adjusted so as to engage and back up the upper end of the punch 61. The punch 61 being nothing more than a flat metal strip of uniform cross-sectional dimensions throughout its length.

curved flatwise to the proper radius, is easily made up from strip. stock and attached to the upper cutter-lever. As will be observed displaced rearwardly. from" stitching posiv tion which inthis figure, is represented by the needle-throat 30 and needle 5.

The punch element 61 is adapted to cooperate with the'die 62 having a slit-like aperture 62 for reception of the lower end of the punch element 61. The die-element 62 is adjustably secured upon the forward extremity .of the lower cutter-lever 60 by means of the screws 62 the shanks of which pass through enlarged apertures 62, Fig. 10, in. the die'v 62. 9 By virtue .of' the adjust-' ments above described the punch and die may be shifted and accurately registered to cutthe buttonhole slit or gap centrally of. the, stitched pattern produced by the machine. 1 q

At their rearward ends the cutter levers 59 and 60 carry the lateral pins or rolls 63 and 64, respectively, which enter the respective slots 65 and .66 extending longitudinally of the auxiliary cutter levers 67 and 68 which are pivoted at 69 to a stationary lug 69' formed on the supporting bracket 69" for the usual stop motion lever s.

The auxiliary cutter levers 67 and 68 carry the respective lateral pins or rolls 7 O, 71 which enter the respective closed camgrooves 72 and 7 8 in the side surfaces of the cam-disks 74, 75 fixed to the cutter shaft 50. The traveling fulcrum block 57 is connect-' ed to the cutter shaft by means of the usual link 76 which is slotted to embrace the cutter shaft and carries aroller 77 enteringacam slot 78 in the face of the usual cutter advancing cam 79 fixed to the cuttershaft. r a

A clamp closing lever 80 is pivoted at 81 to an car 82 formed on the standard 2. This lever is forked at its rearward end to embrace a lateral roll 83 mounted on the auxiliary cutter actuating lever 68. At its forward end the. clamp-closing lever 80 is curved to form a downwardly directed free end 84 which is adapted to engage and depress the arm 44 of the work-clamp to close the latter. Y

The present machine is equipped with a pull-off bar 84 similar to that disclosed in my copending application Serial No.

which is formed with the slot 91 entered by a screw 92 which is threaded into the lever 88. Depending from the rearward arm of the lever 90 is a rod 93 carrying an adjustthe forward movement of the auxiliary cuttel lever 68 .a downward movement of the uli-ofi bar" 8 which deflects the length o' thre between the] tension device 5 and the; ho ow needle-bar 6 and pulls through the tension device an amount of slack-thread suflicient for the needs of the stitching'ihstr'flmentalit'ies in formin the initial 'tches. The amount of t read ull ed 0 ma of course, be varied by adusting the cfollar' 94 on the rod 93, or by adjusting the lever 88 relative to thelever 90. 'fi'w spring97 which iscoiled about the pivot-screw 89serves*to elevate the pull-oif bar 84 after the buttonhole is cut.

In that 'r'ation'of the machine, the work is as usual, the upper clamping foot 29, after which the machine is tripped action by the operator pressing t e usual startin button b which initiates t e action of the cutter-shaft 50. with the parts in the relative positions shown iii Fig. 3, as the cutter-shaft begins to revolve, the cam-rise 98 of the chm-grboe'fh acts through the follower roll 71 toiliPc' the auxiliary cutterelever 68 and thus give a dip to thedie element 62, Fig, 4, 170 carry it under the lower clampplats24 preparatory to the advance of t e cuttin elements into register with the apertime 2 in the lowerwork-clamping plates.

the u ward movement of the anxiliar'y euttrever"68, the 83 acts to swingthe clamp closing leverabout its fulcrumfifto close" the work-clamp before the latter .is shifted out of stitching ition.

' In the present machine the wor -clamp is shifted front stitching to cutting position by mechanism such as disclosed in my said cppendin application Serial No. 317,902. This nice anisih comprisesa cam 9'9, Fig. 2. which oipiatestii'rough a linltlOO connected to the cngitudinal' slide-1ate26. During the rearward movement 0 the clamp under the influence ofth'e cam 99, the cross-slide plate 25 and work-clamping elements are tiltcd pwardly to ca the tongue .31 oiver the" throat-plate 22 to position shown in Fi 5. mechmfism for tilting the chuga com -ices the linifs" 101 whieh'lare piv 'd at f' Mere-nus upon the fixed arms 1'02 ting torwardly'fmm thelied 1'. The i 101. suppo t ar us'ua l cross slide rec 103 which. slfdabljv carries the cross-slide ate 25 thela'tter having spaced Iugsat its under side which receive the red 1'63. Th ends of the rod 103 project beyond the links 101 and enter the vertical slots 105 in the usual side bars of the longitudinal slide frame 26. It will be seen that as the frame 26 is shifted rearwardly to move the work-clamp to cutting position, the links 101 will rock about their pivotal connections with the arms 102 and will lift the cross slide rod 103 and thereby give an upward tilt to the work-clamp. After the links 101 pass their vertical osition the work-clamp is lowered to cuttlng position. This clamp tilting mechanism is fully disclosed in my said copending application Serial No. 317,902. In so far as the use of a traveling buttonhole cutter in connection with" the auxiliarycutter-levers is concerned, however, it is immaterial whether the buttonhole is cut in or out of stitching position, so long as the buttonhole cutting elements are advanced from an inactive position remote from stitching position to a cutting position nearer to or at stitching position.

Aftcr'the buttonhole is cut, the closed cams 72-73 operate positively and with certainty to separate the cutting elements 61. 62, Fig. 5, preparatory to the retraction of said elements to inactive position by the cam 79. By referring .to Fig. 1 it will be seen that the die-element 62 is maintained at a higher level than the work-clamping plates 243K111 as close as ossible to the stitch-forming mechanism wrthout interfering with the circular movement of the post 15' which supports the curved needle 15. If the die 62 were maintained at a lower level, the'cutterlevers and fulcrum block would have to be carried a greater distance rearwardly in order to clear the parts carried by the rotary turret. In order to gain speed, which is a great desiderutum in present day machines. it is very desirable to maintain the cutters as close as possible to cutting position so as to shorten the time required to shift them into and out of such position. During the advance of the cutter levers. the rotary turret and parts carried thereby occupy a position such that the post 15' does not interfore with the dip and forward movement of the die clement 62. Fig. 1 does not show the lower stitch-forming elements in initial position, but merely shows how the post 15 clears the die element 62 during the rotation of the turret.

lVhilc the invention is shown and described as embodied in a buttonhole sewing machine of a particular type, it is not to be understood as limited to a machine of the particular type but may be embodied in buttonhole machines of various types by those skilled in the art. without departure from the invention defined in the claims. The invention, as defined in certain of the appended claims, is not dependent upon the use of the auxiliary cutter levers nor upon the traveling feature of the cutting elements. Neither is the present invention to be understood as limited to a machine for producing a gap buttonhole of any particular size or shape, either straight or eyeletend, or 'l'or producing a buttonhole with its longest dimension disposed in any particular direction relative to the machine bed, except in so far as such features may be specified in certain of the appended claims. lVhile the advantages attributable to the present invention are not confined to its use on any particular material, certain of the advent-aces derived are more prominent in connection with the use of the machine on materials of close or firm texture, as will be readily understood by those skilled in the art.

Having: thus set forth the nature of the invention. what I claim herein is- 1. A huttonhole sewing machine having, in combination, stitch-forming mechanism including an upper depth-stitch needle and a lower curved slit-stitch needle, a workholder, feeding mechanism for relatively moving the stitch-forming mechanism and work-holder to sew around a but-tonhole, buttonhole cutting mechanism comprising a die-element having an elongated aperture and a punch-element adapted to enter said die-element to remove a strip of material extending from end to end of the buttonhole, and means for starting the stitch-tour ing mechanism after the buttonhole has been cut.

2. Buttonhole cutting mechanism tor sewing machines, comprising male and female punch-and-die elements, a pivoted lever upon which said punch element is rigidly mounted, and actuating means incluth ing a closed cam and connections for posi tively tilting said pivoted lever in opposite directions.

3. Buttonhole cutting mechanism for sewing machines comprising, in combination, a frame, pivoted levers carrying rcspectively an apertured die-clement and a punch-element adapted to enter said dieelement, a cutter shaft journaled in said frame. and connections deriving power from said shalt in positively closing and positively opening said pivoted levers, and other connections for bodily shifting said levers to and from cutting position in said frame.

i. A buttonhole sewing machine having, in comliiuation, stitclrforming mechanism, a work-holder, a. buttonhole cutter including pivoted levers carrying coacting cutting elements and occupying a normally inactim position remote from stitching position, a cutter-shaft, a cam on said shaft with connections for advancing the cutter-levers to cutting position, closed cutter actuating cams on said shaft, auxiliary cutter levers actuated. by said cams, and operative connections etween said. auxiliary levers and said cutter-levers for positively closing and positively opening the cutter-levers while in buttonhole cutting position.

5. In a buttonhole sewing machine, in combination, stitch-forming mechanism, a work-clamp, a buttonhole cutter-shaft. cutter-actuating cam on said shaft, an auxiliary lever actuated by cam, a 'tl'lVQling buttonhole cutter-lever operativelyconnected to saic auxiliary lever, and a clamp-- closing lever operatively connected to said auxiliary lever.

in a buttonhole sewing machine, in combination, stitclrtolrming mechanism, a work-clamp, a huttonhole cutter-shalt a cutter-actuating cam on saidshaft, an auxiliary lever actuated by said cam, a traveling buttonhole cutter-lever operatively connected to said auxiliary lever, and a clampclosing lever having a fixed fulcrum and operatively connected to said auxiliary lever.

7. In a buttonhole sewing machine, in combination, stitch-forming mechanism, a work-clamp, a buttonhole cutter-shaft, cutter-actuating cams on said shaft, auxiliary cutter levers actuated by said cams, and traveling buttonhole cutter levers operatively connected with said auxiliary levers.

8. In a buttonhole sewing machine, in combination, stitch-forming mechanism, a work-clamp, means for relatively moving the stitch-forming mechanism and workclamp to sew around a buttonhole, a traveling fulcrum-block, buttonhole cutter-levers pivotally carried by said block, a cuttershait, a cam on said shaft with connections for shifting said fulcrum-block toward and from huttonhole cutting position, a pair of closed cams on said shaft, pair of auxiliary levers actuated by said cams, and operative connections between said cutter-levers and auxiliary levers.

9. In a buttonhole sewing machine, in combination, sti tcl1-i'orming mechanism, a work-clamp, means for relatively moving the stitch-forming mechanism and workclamp to sew around a buttonhole, a traveling fulcrum-block, buttonhole cutter levers pivotally carried by said block, a cuttersha't't, a cam on said shaft with connections for shifting said fulcrum-block toward. and from buttonhole cutting pos' ion, a pair of: closed cams on said shaft, 21. pair of auxiliary levers, actuated by said cams, operative connections between said cutter-levers and auxiliary levers, and a (lanai-closing lever actuated by one of said auxiliary levers.

10. A buttonhole sewing machine having, in combination, stitclrforming:- mechauisn'i, a. work-clamp, feeding mechanism for relatively moving the stitch-forming n'lechanism and work-clamp to sew around a buttonhole, buttonhole cutting mechanism including a pivotally mounted cutter-lever, means for efi'ecting a shift of the worleclamp in moving the work-clamp and buttonhole cutting mechanism into and out of cutting relation prior to sewing, and means actuated by said cutter lever for closing the work-clamp before the shift of the latter is initiated.

11. A buttonhole sewing machine having, in combination, stitch-forming mechanism, a work-clamp, feeding mechanism for relatively moving the stitch-forming mechanism and work-clamp to sew around a buttonhole, buttonhole cutting mechanism including an apertured die element, a punch element adapted to enter said die element, a cutter lever for operating at least one of said elements, means for effecting a shift of the work-clamp in moving the latter and the buttonhole cutting mechanism into and out of cutting relation prior to sewing, and means actuated by said cutter-lever for closing the work-clamp before said shift is initiated.

12.'In a buttonhole sewing machine, in combination, a frame, a cutter-shaft, a pair of closed cams carried by said shaft, a pair of auxiliary levers actuated by said cams, a traveling buttonhole cutter comprising a shiftable fulcrum-block and cutter-levers pivoted thereon, and pin-anrtslot connections between said cutter and auxiliary levers.

13. In a buttonhole sewing machine, in combination, a frame, stitch-forming mechanism, a work-clamp, a cutter-shaft, a pair of closed cams carried by said shaft. a pair of auxiliarv levers actuated by said cams, said levers being fulcrumed on the machine frame, a traveling buttonhole cutter comprising shiftable fulcrum-block and cutterlevers pivoted thereon, pin-and-slot connections between said cutter and auxiliary levers, a clamp-closing lever operatively connected with one of said auxiliary levers independently of the cutter-levers 14. In a buttonhole sewing machine, in combination, independently fulcrumed and operatively connected main and auxiliary cutter-levers, positive actuating means for the auxiliary cutter-levers, and means for shifting the fulcrum of the main cutterlevers toward and away from the fulcrum of the auxiliary cutter-levers.

15. In a buttonhole sewing machine, in combination, independently fulcrumed and slidably connected main and auxiliary cutter-levers, a cutter-shaft, closed cams on said shaft with connections for actuating said auxiliary cutter-lever and an additional cam on said cuttershaft with connections for shifting the fulcrum of the main cutter-levers relatively to the fulcrum of the auxiliary cutter-levers.

16. In a buttonhole sewing machine, a gap buttonhole cutter comprising a lower die sup orting element, an upper pivotally mounted cutter-lever, and an adjustable punch-element carried by said lever and curved substantially concentrically with the fulcrum of said lever.

17. In a buttonhole sewing machine, a gap buttonhole cutter comprising a lower die supporting element, an upper pivotally mounted cutterlever having a seat curved substantially concentrically with the fulcrum of said lever, a punch-element curved to fit said seat and a curved clamping block for holding said cutter-blade firmly against said seat.

18. In a buttonhole sewing machine, a gap buttonhole cutter comprlsing a lower die-supporting element, an upper pivotally mounted cutter-lever having a seat curved substantially concentrically with the fulcrum of said lever, and also having a shoulder at the upper end of said seat, and a punch-element curved to fit against said seat with its upper end in abutting relation with said shoulder, and a curved clamping block for holding said cutter-blade firmly against said seat and in engagement with said shoulder.

19. In a'buttonhole sewing machine, a gap buttonhole cutter comprising pivotally connected upper and lower cutter-levers, a die member carried by said lower lever and formed with a slit-like aperture arranged substantially parallel with the axis of pivotal connection between said levers, and a punch-element detaehably secured to said upper lever and curved substantially concentrically with the axis of said pivotal connection, said punch-element being of substantially uniform cross sectional di- Inensious throughout its length.

2"). In a buttonhole sewing machine, a gap buttonhole cutter comprising a lower die supporting element, an upper pivotally mounted cutter-lever having a seat curved substantially concentrically with the fulcrum of said lever, a punch-element curved to fit said seat and adjustably mounted upon said cutter-lever, and an abutment block adjustably mounted upon said seat at the upper end of said punch element.

21. Buttonhole cutting mechanism for sewing machines comprisinga pivoted carrier lever, a curved punch element carried by said lever and having the form of a thin blade curved flat-wise concentrically with the pivot of said lever, an apertured dieelement adapted to be entered by said punchelement, a cutter-shaft, and means on said shaft and connections for relatively actuating the cutting elements.

22. Buttonhole cutting mechanism for sewing machines comprising a pivoted carrier lever, a punch-element curved concentrically with the axis of the pivot for said lever, an apertured die-element adapted to be entered by said punch-element, and means for securing the punch-element to said lever and adapted to permit endwise adjustment adjusting means for the punch-element of the latter on said lever in the arc of a including opposed gripping Walls curved circle having as a center the axis of the pivot concentrically With the axis of the pivot for for said lever. said carrier lever and permitting endwise 5 23. Buttonhole cutting mechanism for adjustment of the punch-element in the 15 sewing machines comprising a pivoted carcurved path of its operative movement. rier lever, a punch-element curved concen- In testimony whereof, I have signed my trically with the axis of the pivot for said name to this specification. lever, an apertured die-element adapted to 10 be entered by said punch-element, and EDWARD B. ALLEN. 

